The patient came to the clinic 14-March-2019 complaining of LBP for 2 months with left sciatica down to the left ankle area with numbness all toes right foot. MRI lumbar spine performed 19-February-2019 showing extruded disc L5-S1 with left foraminal occlusion. Dynamic studies ruled out overmobility.

On examination: He is in agonizing pain, limping, with exaggerated scoliotic stance. SLRS was 60 degrees right side with pain shooting to the left and 30 degrees in the left with more pain. There was weak dorsiflexion left foot -3/5 and planterflexion same foot -5/5. The left AJ is absent.

The patient was sent for investigations: MRI lumbar spine performed 16-March-2019 showing extruded disc L5-S1 with left foraminal occlusion. Lab investigations were uneventful except for ESR 32 mm/h. The patient was advised for surgery and start immediately Zinnat 500 twice daily to decrease the possibility of postoperative infection.

Foraminotomy left S1 root with reflection of the ligamentum flavum to the right to preserve it. Removal of the extrusion and left sided cleaning L5-S1 disc space. Using MultiGen, bipolar motor stimulation of the left S1 root was achieved with 2.1 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left S1 root was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the left S1 root was achieved with 1.8 V with more brisk response. The patient was put in Reverse Trendelenburg position with Valsalva maneuver. No CSF leak. The fat and ligamentum flavum were repositioned in place. Routine closure of the wound.

Smooth postoperative recovery. The power of the left foot improved and the sciatica disappeared. She was sent to the ward.

There is still an estimated postoperative re-recurrence around 7%, because the disc space height is still not shallow.

This is the 177th case using the BPRF mode with MultiGen. This procedure regained routine acceptance.  It became a usual part of the spine and peripheral nerves surgery. Click here for reference.

It still unclear to evaluate the differences of pre and post application motor responses. The only sure thing that it tells that the electrodes did not migrate during the procedure and the nerve is functioning properly. Here the threshold of stimulation power of motor stimulation of the affected nerve improved after BPRF.

With accumulation of data, it became clear that the irritated nerve with aberrant currents running in the C fibers up, not only causing no change or elevation of the required voltage to achieve motor response, but they could cause the preoperative weakness. Ablation of such currents results in facilitation of the motor response and improvement of function with disappearance of pain.

It is unclear why the roots have several motor response with different patients, despite the fact that the neurological status is the same and the anesthesia protocol also the same.

It could be that the nerve is recovering minute by minute after decompression and this can explain why the motor conductivity is improving after the BPRF application, which require 4 minute session in most cases.

After the 172d case, the elevation of motor stimulation above 5 V was abandoned to avoid delayed dural tear with subsequent CSF leak, which take place at the contact at the lower electrode shaft with the dura below the level of the axilla.